Rachel is unemployed and devastated by a recent divorce. She fills her time with drinking, riding the commuter train, and fantasizing about a seemingly perfect couple the train passes by every day. Then one morning, Rachel sees something shocking that unravels her and entangles her in an unfolding mystery.

Rachel is unemployed and devastated by a recent divorce. She fills her time with drinking, riding the commuter train, and fantasizing about a seemingly perfect couple the train passes by every day. Then one morning, Rachel sees something shocking that unravels her and entangles her in an unfolding mystery.